Astrocytic GLUT1 reduction paradoxically improves central and peripheral glucose homeostasis

Area of Science:

• Neuroscience
• Metabolic Research
• Cellular Biology

Background:

• Astrocytes supply neurons with glucose, crucial for brain energy.
• The role of the primary astrocyte glucose transporter, GLUT1, in brain glucose metabolism remains unclear.

Purpose of the Study:

• To define the necessity of astrocytic GLUT1 for brain glucose metabolism and overall metabolic health.
• To investigate the mechanisms underlying metabolic changes in the absence of astrocytic GLUT1.

Main Methods:

• Generation and analysis of mice with reduced astrocytic GLUT1 (GLUT1ΔGFAP mice).
• Assessment of brain and peripheral glucose metabolism, insulin signaling, and purinergic signaling pathways.

Main Results:

• Astrocytic GLUT1 reduction paradoxically augmented brain glucose metabolism.
• GLUT1ΔGFAP mice showed improved peripheral glucose metabolism, particularly in obesity, indicating enhanced metabolic health.
• GLUT1-deficient astrocytes displayed increased insulin receptor-dependent ATP release.
• Astrocyte insulin signaling and brain purinergic signaling were identified as essential for the observed metabolic benefits.

Conclusions:

• Astrocytic GLUT1 plays a central role in regulating brain energetics.
• Depletion of astrocytic GLUT1 triggers a metabolic reprogramming that sustains brain energy demands, maintains peripheral glucose homeostasis, and supports cognitive function.